The present invention relates to sensing systems for determining relative motion of an object with respect to a reference structure.
Vehicle seat location is being utilized more frequently to control the operation of other vehicle systems. In the prior art, optical decoders which have an optical light source and optical receivers arranged to read a rotating encoder disk are used to determine a precise seat location. This type of seat position sensing system was used, for example, in memory seats. In the memory seat application a precise location of the vehicle seat was required. Other prior art sent position sensing systems have used potentiometers to determine seat position.
A more recent use for seat location information is for controlling a vehicle restraint system. More specifically, it is important to know whether an occupant is in close proximity to an inflatable restraint system, such as an airbag. To increase the effectiveness of an inflatable restraint system the airbag is deployed with less force when an occupant is in close proximity to the airbag. Conversely, when the occupant is farther away from the airbag the airbag is deployed with greater force. Other prior art proximity detection systems use occupant position sensors utilizing infrared, ultrasonic, and radiowave technologies, however these systems have proven to be far too expensive to implement in today""s vehicles and have questionable accuracy.
Therefore, a need exists for a low cost vehicle seat position sensing system which accurately determines the seat position. The system should also prevent debris from interfering with the operation of the sensor system.
In accordance with an aspect of the present invention a sensor system for detecting a movement of a first portion of a structure relative to a second portion of the structure is provided. The sensor system has a flexible retractable member having a first end pivotably attached to one of the first portion of the structure and the second portion of the structure and a second end driven by the other of the first portion of the structure and the second portion of the structure. The flexible retractable member is wound and unwound about the pivotal attachment upon relative movement of the first end with respect to the second end. Further, the flexible retractable member has at least one activation portion and at least one deactivation portion. The sensor system further includes a sensor for detecting the at least one activation portion and the at least one deactivation portion for determining at least one position of the second portion relative to the first portion of the structure.
In accordance with an aspect of the present invention the sensor further comprises an electro-luminescent component in communication with at least one optical receiver.
In accordance with another aspect of the present invention the electro-luminescent component is a light emitting diode.
In accordance with still another aspect of the present invention the electro-luminescent component is an incandescent light source.
In accordance with still another aspect of the present invention the optical receiver is a phototransistor.
In accordance with still another aspect of the present invention the sensor is a magnet in communication with at least one hall effect sensor.
In accordance with still another aspect of the present invention a sensor housing is provided for holding the sensor adjacent the retractable member.
In accordance with still another aspect of the present invention the at least one activation zone is a longitudinally extending slot.
In accordance with still another aspect of the present invention the at least one deactivation zone is a longitudinally extending opaque area.
In accordance with still another aspect of the present invention the at least one activation zone is a longitudinally extending magnetic material.
In accordance with still another aspect of the present invention the at least one deactivation zone is a longitudinally extending non-magnetic area.
In accordance with still another aspect of the present invention the at least one activation zone is a longitudinally extending light reflecting area.
In accordance with still another aspect of the present invention the at least one deactivation zone is a longitudinally extending light non-reflecting area.
In accordance with still another aspect of the present invention a payout spool is provided for winding and unwinding the first end of the flexible retractable member thereabout.
In accordance with still another aspect of the present invention a take-up spool is provided for winding and unwinding the second end of the flexible retractable member thereabout.
In accordance with still another aspect of the present invention a drive spool is provided for rotatably driving the take-up spool in response to movement of one of the first and second portions.
In accordance with still another aspect of the present invention a drive wire is provided having a first drive wire end rotatably attached to the take-up spool and a second drive wire end attached to one of the first and second portions of the structure.
In accordance with yet another aspect of the present invention a sensor system for determining a position of a first portion of a vehicle seat relative to a second portion of the vehicle seat is provided. The sensor system includes a flexible retractable member having a first end pivotally attached to one of the first portion of the seat and a second portion of the vehicle seat and a second end driven by the other of the first and second portions of the vehicle seat, wherein the retractable member has at least one activation portion and at least one deactivation portion and a sensor for detecting the at least one activation portion and at least one deactivation for determining at least one position of the movable portion of the vehicle seat.
The above features, benefits and advantages and other features, benefits and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken together with the accompanying drawings.